D.A. Arthur Branch was the most conservative of the Law & Order District Attorneys. He was politically minded but had definite legal values. My personal favorite.
Executive A.D.A Jack McCoy is a man who is passionate about his beliefs and doesn't always play by the rules. He also has a penchant for falling for his assistant D.A.'s.
A.D.A. Clair Kincaid was the first female A.D.A. on the show. She was beautiful and talented and caught the eye of Jack McCoy. Sadly, she was killed in a car accident.
A.D.A. Serena Southerlyn was the first blond to sit second chair with Jack McCoy. She ended up losing her job and outing herself as a lesbian in her last episode.
A.D.A. Alexandra Borja was a great second chair and kept ol' Jack on his toes. She was the second Law & Order A.D.A. to die on the show. She was murdered and her body was found in the trunk of a car.
A.D.A. Alex Cabot was the first S.V.U. D.A. She was a favorite who survived a gunshot wound and spent time in the witness protection program. The character crossed over to the short lived Law & Order: Trial By Jury.